A Wideband Millimeter-Wave Frequency Synthesis Architecture Using Multi-Order Harmonic-Synthesis and Variable $N$-Push Frequency Multiplication

This paper proposes an architecture and design approach for the realization of wideband millimeter-wave frequency synthesizers. This architecture uses two-step multi-order harmonic generation of a low frequency phase-locked signal to generate wideband millimeter-wave frequencies. The first step is implemented using a multi-order digital harmonic synthesis block combined with a multi-phase injection-locked oscillator. A variable
N
-push frequency multiplier uses the output of the oscillator to implement the second harmonic generation step. A prototype of the proposed system is designed and fabricated in 90 nm CMOS technology. Measurements show that using a phase-locked input signal of 1-1.43 GHz, the system can provide an output which covers the frequency range of 5-32 GHz. This represents a tuning bandwidth of 27 GHz with a tuning range of 146%. The measured phase noise at 1 MHz offset is -116 dBc/Hz and -99 dBc/Hz at 5 GHz and 32 GHz, respectively.